Resin recycling system

ABSTRACT

A system for recycling reusable resin mold products recovered from discarded apparatuses is disclosed. This recycling system includes a crushing system for crushing resin mold products one kind by one kind into crushed resinous pieces and packing the same in a bag, a classification system for irradiating a light beam to the resin in the bag and classifying the bags into respective kinds of resins based on a reflected beam therefrom, a cleaning system for separately cleaning the respective kind of crushed resinous pieces taken out of the bag to remove foreign matters adhered onto the surfaces of the crushed resinous pieces therefrom, and a recovery system for recovering the cleaned crushed resinous pieces.

This application is based on Patent Application Nos. 2000-256202 filedAug. 25, 2000 in Japan and 2001-047750 filed Feb. 23, 2001 the contentof which is incorporated hereinto by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a system for recycling resinousmaterials from resin mold products recovered from discarded apparatuses(such as home electric appliances, electronic devices or cars), moreparticularly to a crushing system for crushing polymer parts obtained bydisassembling the recovered products to reduce the volume thereof; aclassifying system for classifying the resinous materials into theirkinds, preferably into kinds of fire retardants added thereto; and acleaning system for removing foreign matters such as coated films,labels or seals applied to the products or other contamination thereof.

2. Description of the Related Art

Plastics light in weight and excellent in mechanical strength have oftenbeen used for home electric appliances, OA apparatuses, communicationapparatuses or others as internal parts or external casings thereof.From a point of view of the environmental protection, the conversionfrom a mass-production/mass-scrap economy in the past to a circulationtype economy is required. In such a recent trend, a full-scale recycleof resinous products has been urgently demanded; for example, therecycling of home electric appliances has been obligated by law.However, regarding the material recycle in which the resin mold productsare recovered and reused as resinous materials, it is done solely in acase wherein it is possible to specify to some extent what kind of resinis used, because there is a problem peculiar to the resin in that ifdifferent kinds of resins are mixed together, functions inherent to theresin are significantly damaged. Accordingly, a resin recycling systemis desired, which is capable of correctly classifying various kinds ofresinous products used in the discarded appliances or apparatuses andregenerating the same as fresh resinous materials for the home electricappliances, OA apparatuses or communication apparatuses.

To proceed a high-quality recycling, it is necessary to correctlyidentify and classify materials of resin mold products containingvarious kinds of additives including fire retardant. Regarding theidentification of materials of the resin mold products, ahigh-performance resin identification device has recently beendeveloped, and is becoming reality. This device, however, necessitates aconsiderable care on the operation, maintenance and inspection thereofas well as it is expensive in cost. The most effective method foridentifying materials of the resin mold products solely from a point ofview of the material identification is to provide such a resinidentification device in each of the disassembly factories. This methodis, however, problematic from the economical view point or a view pointof stable operation of the system.

To operate the above-mentioned resin identification device under thestably controlled condition, it is desirable to provide the disassemblyfactory for recovering the resin mold products at a position differentfrom that of the resin identification device. In such a case, it isnecessary to convey the resin mold products from the disassembly factoryto the position at which the resin identification device is provided.

However, the resin mold products obtained from the discarded apparatuseshave various shapes and sizes distributed from a small one to anextremely large one. Therefore, if they are packed into a box or a bagwhile maintaining their shapes, the physical transportation cost becomeswasteful since a bulk specific weight is very small to reduce a weightrelative to a volume thereof. Accordingly, it is desired to crush theresin mold products into pieces having an economically preferable size(a size capable of achieving a proper transportation efficiency). As acrusher used for this purpose, it is possible to use a commerciallyavailable crusher such as a hammer mill, a cutter mill, a two-axiscrusher and the like which is capable of crushing the resin moldproducts into pieces having about 50 mm or less in size.

However, the resin mold products recovered from disassembling applianceshave various sizes as set forth above. In order to load all of the resinmold products and crush them into pieces having about 50 mm or less insize, it becomes necessary to provide a very big crusher having aloading opening. Since these equipment is costly, there is a problemthat it is economically impossible to install such expensive equipmentat each of small factories.

Further, if the resin mold products are crushed altogether by suchmeans, however, many of the resin mold products formed of differentkinds of resins are crushed in a mixed state, and, as a result, it isnecessary to identify crushed pieces in which many kinds of resins existusing an identification apparatus. Although such identification ispossible in principle, industrialization thereof is difficult inpractice because it is necessary to respectively identify kinds ofresins of a large number of crushed pieces and classify the same intothe respective materials after the identification.

In addition, to economically realize the material recycling ofhigh-quality resinous materials, it is necessary to classify kinds ofresins containing various additives such as fire retardant at a highaccuracy and a high speed. As a method for classifying the kinds ofresins, a technique using, for example, a near infrared ray absorptionhas been known and various devices are marketed. However, this methodhardly identifies kinds of resins with many identification errors and isunsuitable for the high accuracy and high speed identification. Anothermethod utilizing intermediate infrared absorption has been also known.Although this method is capable of identifying not only kinds of resinsbut also those of additives such as fire-retardant at a high accuracy,there is a problem in that a long time is required for theidentification and therefore unsuitable for a high speed processing.

On the other hand, the recovered resinous products may be coated withfilms, applied with labels or the like or carry various contaminants,which are liable to enter the resin during the treatment of the resinousproducts to result in a problem to significantly deteriorate thecharacteristic of the resin to be reused.

Although various trials have been attempted for removing foreign matterscarried on the surface of the resinous product, for example, by amechanical method and the separation or removal with a solvent, there isa problem in either cases. For instance, if the removal of the coatedfilm or the label is intended by using a crusher such as a ball mill,the resin is softened due to heat generated by the friction during thecrushing operation, which disturbs the resin removal or causes there-adhesion of the foreign matters once removed. Also, there is anothermethod wherein the foreign matters are dissolved with a solvent and thenseparated and removed from the resin. This method, however, has aserious problems in that the used solvent must be regenerated ordiscarded, and also has other problems in that an apparatus usedtherefor is complicated in structure and unfavorable from the economicalpoint of view.

There is a still further method for removing the coated film or labels,called as a dry blast treatment, wherein an abrasive material such assands or metallic particles is used for scraping off the foreign mattersfrom the surface of the resinous product. According to this method,however, particles of the abrasive material may stick into the surfaceof the resinous product and remain as they are as new foreign matters.Also, the resin may be softened by heat generated due to the friction ofthe abrasive material and cause the re-adhesion of the foreign mattersonce removed.

SUMMARY OF THE INVENTION

The present invention has been done to solve the above-mentionedproblems, and an object of the present invention is to provide a resinrecycling system for crushing resin mold products collected fromdiscarded apparatuses into crushed resinous pieces to reduce an apparentvolume thereof, without identifying that the resin mold product belongsto what kind of resin but with taking care that a plurality of kinds ofresins are not mixed with each other; identifying a kind of the crushedresinous pieces to classify the same to that kind for easily determininga field in which the same is reused; and removing foreign matters fromthe surface of the classified crushed resinous piece to be reusable asresinous material.

Another object of the present invention is to provide a crushing systemfor roughly crushing polymer parts (including a large-sized ones) takenout from the collected and disassembled apparatuses to reduce anapparent volume thereof.

A further object of the present invention is to provide anidentification system for effectively identifying a kind of crushedresinous pieces obtained by crushing resin mold products collected fromdiscarded electric or electronic equipment without identifying that theresin mold product belongs to what kind of resin but with taking carethat a plurality of kinds of resins are not mixed with each other.

Further, the present invention is to solve the above-mentioned problemsof the prior art by providing a cleaning system for thermoplastic resinproducts wherein, when the resin products are collected and cleaned tobe reusable resinous material, foreign matters such as coated films orlabels adhered on the surface of the resin products are sufficientlyremoved therefrom so that the resinous material is usable in the samefield as before.

To achieve the above objects, according to one aspect of the presentinvention, a resin recycling system is provided, which comprisescrushing means for individually crushing resin mold products intocrushed resinous pieces in which 70% or more of the crushed resinouspieces have an equivalent diameter in a range from 1 to 50 mm, packingmeans for packing the crushed resinous pieces of the respective moldproduct into a bag having a transparent portion, classification meansfor irradiating a light beam to the crushed resinous pieces in the bagthrough the transparent portion, identifying a kind of the crushedresinous pieces based on a reflected beam therefrom, and classifying thebags into respective kinds of resins, and cleaning means for taking thecrushed resinous pieces out from the bag and cleaning the crushedresinous pieces of the respective kind to remove foreign matters adheredon the surface thereof.

In the above description, the term, “equivalent diameter” is a diameterof a circle having the same area as that of a projected area of anobject.

Here, the equivalent diameter of the crushed resinous piece ispreferably in a range from 3 to 40 mm, more preferably from 5 to 30 mm.A ratio of the crushed resinous pieces having the equivalent diameterwithin these ranges is preferably 80% or more, more preferably 90% ormore.

If the equivalent diameter of the crushed resinous piece is smaller than1 mm, there is an inconvenience in that foreign matters could not beremoved during cleaning by the cleaning means, because the crushedresinous piece is pulverized. For example, when the cleaning is carriedout by the abrasion, the abrasion becomes impossible. Also, the smallresinous pieces are liable to stick to the interior of the crusher orthe bag due to static electricity.

On the other hand, if the equivalent diameter of the crushed resinouspiece exceeds 50 mm, the crushed resinous pieces may be stillthree-dimensional to obstruct the sufficient volume reduction.

The crushing may be carried out at one step. However, if the moldproduct is too large in size to be introduced into an ordinary crusher,the crushing may be carried out at two steps wherein the mold product isroughly crushed by a rough crusher and then introduced into the ordinarycrusher.

Since one resin mold product is formed of one kind of resin, it ispossible to effectively reduce the apparent volume of the resin moldproduct while preventing the finely crushed resinous pieces from mixingwith other kinds by crushing the resin mold product separately one kindby one kind and immediately packing into a bag. By crushing the resinmold product one by one which is recovered from the discarded apparatusin the manual disassembly factory and packing the crushed resinouspieces in a bag, the conveying efficiency is enhanced.

Since the crushed resinous pieces in the bag is of the same kind ofresin, it is possible to carry out the economical classification byclassifying the bags.

In this regard, to further enhance the working efficiency, when it isapparent in advance that the mold products are formed of the same kindof resin, they are crushed together and packed in one bag. For example,if there are plurality of mold members of the same shape and function(such as paper feeding trays of different sizes of a copying machine)and it is confirmed that they are formed of the same kind of resin, theymay be crushed together and packed in one bag. This method is favorablefor facilitating the working efficiency when there are a number of smallresinous members of a similar shape and the same kind of resin in onediscarded apparatus.

The transparent portion of the bag is necessary for the purpose ofpreventing the light beam irradiated to the crushed resinous particlesor reflected therefrom from being adversely effected by the passagethereof through the bag. Accordingly, if the adverse effect on thedetection due to the passage of light beam through the bag isnegligible, the transparent portion is not necessarily completelytransparent. In short, it is sufficient that the bag is provided with alight-passing area (transparent portion) which does not adversely effectthe detection, and in this text, such a light-passing area is referredto as a transparent portion. The transparent portion may extendthroughout the bag. Such a bag may be formed, for example, ofpolyethylene. In this regard, a thickness of the transparent portion isgenerally 100 μm or less. Other materials may be used for this purpose,such as resinous film, resinous net or metallic net.

A method for identifying a kind of resin includes, for example, onebased on a Raman spectrum analysis, wherein a Raman spectrum obtainedfrom the reflected light beam from the resin to be inspected (i.e., thecrushed resinous pieces in the bag) is sequentially compared with Ramanspectra obtained from reflected light beams from various known resinsprepared in advance to find whether or not there is the coincidencebetween both the spectra. The method based on the Raman spectrumanalysis is favorable because it is less adversely effected from colortone or surface contamination of the crushed resinous piece. One methodfor identifying kind of resin based on the Raman spectrum analysis isdisclosed, for example, in paragraphs from 0011 to 0018 of JapanesePatent Application Laid-open No. 10-38807. Alternatively, an infrared ornear infrared spectrum analysis may be used for this purpose.

One method for classifying the bags into kinds of resins includes thesteps of storing an identified kind of crushed resinous pieces and anexpected arrival time at which the bag of the crushed resinous pieceswould reach a predetermined classification position on a conveying path,in correspondence to each other, and recovering the bag reaching theclassification position at the expected arrival time from the conveyingpath.

The predetermined classification position may be different in accordancewith kinds of resins. In such a case, the classified recovery is carriedout wherein, for example, the bag in which resin A is packed isrecovered from the conveying path at the classification position for theresin A, and the bag in which resin B is packed is recovered from theconveying path at the classification position for the resin B.

The predetermined position may be a specified one irrespective of kindsof resins. In such a case, the classified recovery is carried out insuch a manner that the bag of resin A (the resin A is packed) reachingthe classification position is guided from the conveying path to acollecting container or the like for the resin A, and similarly, the bagof resin B reaching the classification position is guided from theconveying path to a collecting container or the like for the resin B.

The expected arrival time is obtained by an identification time, adistance between an identification position and the classificationposition, and a conveying speed. While the expected arrival time may becalculated from these data every time, it may be determined as a time apredetermined period after an identification time, since the abovedistance and the conveying speed are constant.

The cleaning means removes foreign matters such as plated layers,coatings, labels or contaminants adhered to the surface of the crushedresinous piece therefrom.

The cleaning means may be a device having a cleaning vessel and anagitator member provided in the cleaning vessel wherein at least part ofthe inner wall of the cleaning vessel and/or a surface of the agitatormember has an abrasive surface (roughened surface) for removing(scraping or scrubbing off) the foreign matters on the surface of thecrushed resinous piece. Water or an aqueous rinsing liquid may besupplied into the vessel to enhance the removal of foreign matters.

The abrasive surface (roughened surface) may be of any structure,provided it could sufficiently clean the surface of the crushed resinouspiece. The abrasive surface preferably has the irregularity having adepth in a range from 40 to 2000 μm. By the contact of crushed resinouspieces with this roughened surface having such irregularity, foreignmatters such as coated film or label adhered onto the surface of thecrushed resinous piece are sufficiently scrubbed or scraped off andremoved. If the depth of the irregularity is less than 40 μm, theforeign matters are not sufficiently removable. Contrarily, if exceeding2000 μm, the surface of the crushed resinous piece is excessivelyscraped off to lower the resin recovery percentage. The depth of theirregularity is preferably in a range from 50 to 1000 μm, morepreferably from 60 to 500 μm. If the depth is within such a range, theforeign matters are not excessively scraped off but sufficientlyremovable.

In the device for continuously cleaning the crushed resinous pieces, thecrushed resinous pieces are continuously supplied from one end of thecleaning vessel, conveyed in one direction within the cleaning vessel,for example, by a screw or others and continuously collected from theother end. If water or aqueous liquid is used in such a device, thefeeding of water or aqueous liquid is carried out in a similar mannerthat the water or the aqueous liquid is also continuously fed from theone end and/or intermediate portions of the cleaning vessel, flows inthe same direction in the cleaning vessel and is continuously drainedfrom the other end.

When water or aqueous liquid is used during the cleaning operation, itfunctions as a lubricant between the crushed resinous pieces and theirregularity to prevent the surface of the crushed resinous piece frombeing excessively scraped off as well as to suppress the temperaturerise of the crushed resinous piece due to the cooling operation of waterwhereby the softening thereof is inhibited. Also, the foreign matterssuch as coated film or label once removed are quickly discharged out ofthe cleaning device and do not adhere again to the crushed resinouspieces.

The resin recycling system may have a recovery means for separatingforeign matters from a mixture of the crushed resinous pieces cleaned bythe cleaning means and the foreign matters and recover the crushedresinous pieces. The crushed resinous pieces and the foreign matters maybe separated from each other, for example, by wind. Also, magnet forcemay be used for removing metallic material. When water or aqueous liquidis used for the cleaning operation, it is possible to remove foreignmatters together with water or the like. In this regard, it may be soadapted that, after removing foreign matters from water or aqueousliquid through a filter or others, the water or aqueous liquid isreused.

The resin mold products which can be recycled after being crushed,classified and cleaned according to the present invention include, forexample, those used as housings or parts of various apparatuses used inan OA and home electric appliance field, an electric and electronicfield, a sanitary field, an automobile field or a sundries field. Forexample, various resinous housings, trays or internal resinous partsused in copying machines, printers, personal computers, TV sets, variousmonitors or mobile telephones.

The resinous material recycled according to the present inventionincludes, for example, various styrene type resins such asacrylonitrile-butadiene-styrene resin, polystyrene resin oracrylonitrile-styrene resin; polycarbonate resin; olefin type resin suchas polyethylene or polypropylene; polyamide type resin such as PA 6,PA66, PA46 or PA12; polyester type resin such as polybutyleneterephthalate, polyethylene terephthalate or polyacrylate; polyphenyleneether resin; polyacetal; polyvinylchcloride resin; polysulfon; PPS;polyether sulfon; ethylene-vinylacetate copolymer;ethylene-ethylacrylate copolymer; EVOH; polyamide type elastomer;polyester type elastomer; and alloys in which two or more of them aremixed. These are all identifiable by the classification means of theinventive system.

The classification means of the inventive system can identify additivescontained in the crushed resinous pieces, such as variousfire-retardants including halogen type and phosphor type; variousfire-retardant assistants such as antimony trioxide, antimony tetroxide,antimony pentoxide, chlorinated polyethylene or tetrafluoroethylenepolymer; inorganic filler such as glass fiber, carbon fiber, metallicfiber or talc; anti-fungus agent, mildewcide, plasticizer, antistatic orsilicone oil. These additives are identifiable if a considerable amountof them is contained in the crushed resinous piece (resin mold product),for example, 1 part by weight or more, preferably 2 parts or more in 100parts by weight of the resin mold product.

To achieve the above objects, one aspect of the crushing systemaccording to the present invention comprises an endless conveyor forconveying polymer mold products, and an opposed member having an opposedsurface confronting at least one end of the endless conveyor on theconveying-directional side and disposed so that a distance between theopposed surface and a conveying surface of the endless conveyor becomessmaller in the conveying direction, wherein crushing edges or crushingpins are provided on at least one of the conveying surface of theendless conveyor and the opposed surface of the opposed member, todirect toward the other, whereby the polymer mold products transportedby the endless conveyor are pushed into a gap between the conveyor andthe opposed member and crushed with the crushing edges or pins.

The crushing edge or pin is a member having a function for crushing thepolymer mold product conveyed by the endless conveyor and pushed into agap between the same and the opposed member. That is, even though shapesthereof are different from those generally thought from the feeling ofwords “edge or pin”, any member may be the crushing edge or pinaccording to the present invention, if it is provided on at least one ofthe conveying surface of the endless conveyor and the opposed surface ofthe opposed member to direct toward the other, and has theabove-mentioned crushing function. The crushing edge or pin preferablyhas a sharp portion to be in contact with the polymer mold productbecause a larger crushing performance is exhibited thereby.

Preferably, the crushing edges or pins are provided on the conveyingsurface of the endless belt, and recesses or holes are provided on theopposed surface of the opposed member for allowing tip ends of thecrushing edges or pins provided on the endless conveyor to pass throughthe same.

The opposed member may be a second endless conveyor.

To achieve the above-mentioned objects, one aspect of the identificationsystem of the present invention is an identification device forirradiating a light beam to a polymer products conveyed by conveyormeans, detect the reflected beam or the dispersed beam from the polymerproduct by a sensor element, and identify a kind of the polymer productbased on the detected result, wherein the sensor element is disposed ata predetermined position in the vicinity of a conveying path of thepolymer product, and a distance determination mechanism is disposed inthe conveying means or in the vicinity thereof, for opposing the polymerproduct passing by the sensor element to the sensor element at adistance between the both.

Selectable polymers include, for example, rubber-like polymer,thermoplastic elastomer and resin. Of them, resin is more preferable.Additives in the resinous material and the selectable polymeric materialare the same as described above.

The conveyor means may be an endless conveyor and the sensor element maybe disposed at a predetermined position beneath the conveying pathconstituted by the endless conveyor, and the distance determinationmechanism may be a light window provided at each of portions of theendless conveyor passing over the predetermined position.

According to this arrangement, the light beam is irradiated from beneathto the polymer conveyed on the endless conveyor through the lightwindow, and the reflected or disperse light beam is received by thesensor element through the light window. The light window may be a mereslit but not be limited thereto. It may be formed of any light-permeablematerial unless it disturbs the detection of Raman disperse rays.

Alternatively, the conveyor means may be an endless conveyor and thesensor element may be disposed at a predetermined position on a side ofthe conveying path constituted by the endless conveyor, and the distancedetermination mechanism comprises a stopper member having a light windowand disposed in front of the sensor element in the vicinity thereof anda guide for guiding the polymer product carried on the endless conveyorso that the polymer product is pushed against the light window of thestopper member to be able to pass by a front of the sensor element.

The stopper member has a function for limiting the displacement(deviating from the conveying direction) of the polymer pushed towardthe stopper member by the guide while being conveyed on the endlessconveyor at the position of the stopper member. The stopper member isprovided with the light window, behind which is located the sensorelement.

According to this arrangement, the polymer conveyed on the endlessconveyor is guided by the guide to be brought into contact with thelight window of the stopper member and irradiated with a light beamthrough the light window. The reflected or dispersed beam thereof isreceived by the sensor element through the light window. The lightwindow may be a mere slit or be formed of any light-permeable materialsuch as transparent glass plate not disturbing the detection of Ramandisperse rays.

To achieve the above objects, one aspect of a method for cleaningthermoplastic resinous products comprises the steps of crushing thecollected thermoplastic resinous products into crushed pieces, supplyingthe crushed pieces together with water into a cleaning device having avessel and a rotary body disposed in a rotatable manner within thevessel, wherein at least part of the inner surface of the vessel and/ora surface of the rotary body to be in contact with the crushed resinouspieces is roughened, and rotating the rotary body to clean the crushedpieces.

According to this cleaning method, at least part of the inner surface ofthe vessel and/or a surface of the rotary body is roughened. Theroughening may be carried out in any manners, provided the resin productcould be sufficiently cleaned. Preferably, the surface irregularity hasa depth in a range from 40 to 2000 μm. When the roughened surface isbrought into contact with the crushed resinous pieces, foreign matterssuch as coated film or label adhered on the surface of the crushedresinous piece are sufficiently scrubbed or scraped off and removed. Ifthe depth of the irregularity is less than 40 μm, the foreign mattersare not sufficiently removable, while if exceeding 2000 μm, the surfaceof the crushed resinous piece is excessively scraped off together withresin to lower the recovery percentage of resin. The depth of theirregularity is preferably in a range from 50 to 1000 μm, morepreferably from 60 to 500 μm. If the depth is within this range, theforeign matters are sufficiently removed without excessively scrapingresin off from the crushed piece.

The roughened surface in the interior of the vessel is preferably 1% ormore, preferably 5% or more, more preferably 10% or more of a total areaof the inner surface of the vessel and the surface of the rotary body tobe in contact with the crushed resinous pieces. Degrees of thesurface-roughening by the irregularity may be approximately equal orunequal both in the inner surface of the vessel and in the surface ofthe rotary body. The degree of the irregularity may be equal or unequalthroughout the roughened inner surface of the vessel and/or theroughened surface of the rotary body.

According to this cleaning method, water is continuously supplied duringthe cleaning operation and acts as a lubricant between the surface ofthe crushed resinous piece and the roughened surface having theirregularity to prevent the surface of the crushed resinous piece fromexcessively being scraped off. Also, by the cooling action of water, thetemperature rise in the crushed resinous piece can be prevented. Foreignmatters such as coated film or label which have been once removed arequickly discharged out of the cleaning device not to adhere again to thecrushed resinous pieces. Further, water is preferably continuouslysupplied and drained so that a water level in the cleaning device ismaintained constant, while taking care to maintain a ratio in weight ofthe crushed pieces to the water constant, because the respective crushedresinous pieces continuously supplied can be evenly cleaned.

The cleaning is preferably carried out so that the ratio in weight ofthe crushed pieces to the water in the cleaning device is controlled tobe 1:0.3 to 2 and water is continuously supplied and drained to maintainthe interior temperature of the cleaning device at 70° C. or lower. Ifthe ratio of water is less than 0.3, the interior of the cleaning deviceis not sufficiently cooled, whereby the temperature rises above 70° C.to soften and melt the crushed resinous pieces, which may disturb thecleaning operation. On the other hand, if the ratio of water exceeds 2,chances of contact of the crushed resinous pieces with the inner surfaceof the vessel and the surface of the rotary body, particularly thoseroughened to have the irregularity, becomes fewer. Even if the contactoccurs, the crushed resinous piece does not be sufficiently pressed ontothe surface, whereby the foreign matters such as coated film or labelmay not be completely and effectively removed.

Further, the rotary body has a screw blade for conveying the crushedresinous pieces and cleaning plates or pins for cleaning the crushedresinous pieces around a rotary shaft, and preferably rotates so that alinear speed of a tip end of the cleaning plate or pin is in a rangefrom 0.5 to 20 m/sec. If the linear speed is 0.5 m/sec or less, thecleaning becomes insufficient, while if exceeding 20 m/sec, the interiortemperature of the device rises, whereby it is difficult to maintain thetemperature at 70° C. or lower.

According to the above-mentioned method, it is possible to clean thecrushed pieces of all thermoplastic resin products molded to havepredetermined shapes by various molding methods such as compressionmolding, ejection molding or blow molding. These resin mold products maybe molded either using a mold or using no mold but a mold die or others.Examples of the resin mold product include not only housings of homeelectric appliances such as TV sets or electric refrigerators orhousings of OA equipment such as personal computers or printers but alsoparts of these apparatuses and/or broken ones thereof.

Although there is no limitation in kinds and shapes of the resinproducts, preferably, products of different kinds of resins are notmixed together. This is because, if different kinds of resins are mixedtogether, in general, characteristics inherent to the respective resinare largely deteriorated. Therefore, the resin products are preferablyclassified to the respective kinds and separately cleaned in advance.Also, the resin products may preferably be classified to have the sameor similar color tones, such that products which color tones are largelydifferent, for example, one being pale and light gray and the otherbeing deep and dark gray, are not mixed together. If the products havinglargely different color tones are not mixed together, color tone ofresin to be reused is easily adjustable.

Also, there is no limitation in size of the resin products, providedthey can be crushed to pieces of a suitable size.

The resin products may be coated or plated. The coated film may be ofany material usually used for coating resin. The plated layer may be ofany metal usually used for plating resin.

The resin product is cleaned after being crushed into resinous piecesthrough a crushing operation in advance. The crushing operation may becarried out by a crusher usually used for crushing resin and capable ofcrushing the resin product into pieces of a size suitable for thecleaning, such as a hammer mill or a cutter mill. The crushing operationis preferably carried out under the forced cooling such as air coolingso that the resin product does not melt due to the heat generation.

The maximum length of the crushed resinous piece is preferably in arange from 1 to 30 mm, more preferably from 2 to 20 mm, most preferablyfrom 3 to 10 mm. If the maximum length is less than 1 mm,micro-particles increases to dissipate the crushed resinous pieces in apre-treatment process. On the other hand, if exceeding 30 mm, thecleaning becomes insufficient all over the surface of the crushed piece.There is no limitation in shape of the crushed resinous piece providedno problem occurs in the handling thereof. However, an excessivelyelongated one is unfavorable, and one having generally equal dimensionsin all directions in a plan view is preferable, such as circular orsquare. Crushed resinous pieces of such a shape can be effectivelycleaned even if an amount thereof is large. In this regard, ifnecessary, small crushed resinous pieces having the maximum length ofapproximately 1 mm or less, metallic powder or dust may be removed aftercrushing by a vibratory screen or others.

To achieve the above objects, in the cleaning system according to thepresent invention, a device is provided for cleaning thermoplasticresinous products comprising a vessel and a rotary body built-in in thevessel, wherein the vessel has an entrance port for the thermoplasticresinous products provided in an upper area of one end thereof, an exitport for the thermoplastic resinous products provided in a lower area ofthe other end thereof, a water supply port and a drainage port; thedrainage port being connected to a drainage line for adjusting a waterlevel; the rotary body having a rotary shaft, a screw blade provided onthe circumference of the rotary shaft and at least one of a plurality ofcleaning plates and cleaning pins; and at least part of the innersurface of the vessel and/or surfaces of at least one of the cleaningplates and the cleaning pins being roughened.

Also, to achieve the above objects, in the cleaning system according tothe present invention, a device is provided as another aspect forcleaning thermoplastic resinous products comprising a vessel andagitating blades, wherein the vessel has an entrance port for crushedresinous pieces and a water supply port, both provided in an upperportion thereof, and an exit port for the crushed resinous pieces and adrainage port, both provided in a lower portion provided thereof; adrainage line for adjusting a water level being connected to thedrainage port, and at least part of the inner surface of the vesseland/or surfaces of the agitating blades being roughened.

According to the above-mentioned cleaning device, at least part ofsurfaces to be in contact with the crushed resinous pieces is roughenedto effectively scrub or scrape off a surface portion of the crushedresinous piece and sufficiently remove foreign matters such as coatedfilm, plated layer applied to the surface, label or seal adhered to thesurface or contaminants. At least part of the inner surface of thevessel and/or a surface of at least one of the screw blade, the cleaningplate and the cleaning pin may be roughened. Preferably, the innersurface of the vessel and a surface of at least one of the screw blade,the cleaning plate and the cleaning pin are roughened. Regarding thescrew blade, the cleaning plate and the cleaning pin, a surface of atleast one of the screw blade and/or the cleaning plate is morepreferably roughened. Also, the inner surface of the vessel and at leastpart of a surface of the agitator blade is preferably roughened.

If necessary, the cleaning device may be combined with a water rinsingdevice, a dehydrator, a dryer, a vibratory screen, a wind typeclassifier and/or a metal sensor to assuredly remove foreign matterssuch as coated film, label or contaminants and obtain pure crushedresinous pieces. Such crushed resinous pieces may be used in any fieldrequiring the same with no problems.

The above and other objects, effects, features and advantages of thepresent invention will become more apparent from the followingdescription of embodiments thereof taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram for schematically illustrating a resinrecycling system according to the present invention;

FIG. 2 is a schematic view of one embodiment of crushing means andclassifying means used in the present invention;

FIG. 3 is a schematic side view of one example of a crusher used in thepresent invention;

FIG. 4 is an enlarged view of part of FIG. 3;

FIG. 5A is a front view of an opposite wall; FIG. 5B is a sectional viewtaken along a line 5B—5B in FIG. 5A; FIG. 5C is a plan view of aconnecting plate of a chain conveyor; and 5D is a sectional view takenalong a line 5D—5D in FIG. 5C;

FIG. 6A is a schematic side view of another example of a crusher; andFIG. 6B is a schematic side view of a still further example thereof.

FIG. 7 is a block diagram illustrating the relationship between inputsand outputs of a controller for the system shown in FIG. 2;

FIG. 8 is a flow chart illustrating one example of a procedure forcontrolling the identification and classification/recovery of resins;

FIGS. 9A and 9B are a side view and a top view, respectively, of oneexample of a polymer conveying mechanism provided with an identificationdevice;

FIG. 10 is a sectional view taken along a line 10—10 in FIG. 9A;

FIGS. 11A and 11B are a side view and a top view of another example of apolymer conveying mechanism provided with an identification device;

FIG. 12 is a cross-sectional view of one example of a horizontal typecontinuous cleaning apparatus according to the present invention;

FIG. 13 is an elevational sectional view of one example of a horizontaltype continuous cleaning apparatus according to the present invention;

FIG. 14 is a sectional view illustrating a drainage line for adjusting awater level of a cleaning apparatus;

FIG. 15 is a cross-sectional view illustrating one example of a verticaland batch type cleaning apparatus according to the present invention;

FIG. 16 is a block diagram illustrating one embodiment of recovery meansaccording to the present invention;

FIG. 17 is a table showing results obtained by the operation of acrusher;

FIG. 18 is a table showing results obtained by the operation of aidentification device; and

FIG. 19 is a table showing results obtained by the operation of variouscleaning apparatuses.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

FIG. 1 illustrates one embodiment of a resin recycling system accordingto the present invention.

The illustrated system includes a crushing system 200, a classificationsystem 400, a cleaning system 600 and a recovery system 800. Thecrushing system 200 operates to crush resinous mold products one by oneinto pieces so that 70% or more of the pieces have an equivalentdiameter in a range from 1 to 50 mm, and to pack the pieces of every onemold product to one transparent bag. The classification system 400operates to irradiate light beams to the crushed resinous pieces in thebag, determine a kind of the crushed resin in accordance with thereflected beams therefrom and classify the respective bags into thekinds of resins. The cleaning system 600 operates to clean the crushedresinous pieces taken out from the respective bags classified by theclassification system 400 to remove foreign matters on the surface ofthe crushed resinous pieces. A mechanism for taking out the crushedresinous pieces from the bag and sending the same to a rinsing mechanismmay be provided. The recovery system 800 operates to separate theforeign matters from a mixture thereof with the cleaned resinous piecesto recover the crushed resinous pieces.

[1] Crushing System 200 and Classification System 400

Initially, the crushing system 200 and the classification system 400will be described with reference to FIG. 2.

The crushing system 200 has a resin crusher 21. The resinous piecescrushed by the resin crusher 21 are packed in a transparent bag 25attached at a lower position of the crusher.

As described later, the classification system 400 has a conveyor device49 for the bags 25, a resin identification device (resin determinationdevice) 41 and classified recovery devices 47 a to 47 c.

The resin crusher 21 is a device for crushing the resin mold productinto pieces so that 70% or more of the pieces have an equivalentdiameter in a range from 1 to 50 mm. The resin mold products are crushedinto pieces one by one and packed in the bag 25 attached to a lowerposition of the resin crusher 21. While the resin crusher 21 illustratedin the drawing is of a type carrying out the crushing operation in onestep, the operation may be carried out in two steps if the moldedproduct is too large to be introduced into the ordinary size crusher.For example, a crusher for carrying out the coarse crushing and one forcrushing the coarsely crushed pieces into smaller pieces having anequivalent diameter in a range from 1 to 50 mm may be provided.

The bag 25 is made of transparent polyethylene and has a size of 23 cmlong, 17 cm wide and 40 μm thick. The bag 25 may be opaque and made ofother material than polyethylene unless the identification of thecrushed resin is disturbed thereby in a resin identification device 41described later. Also, the bag may be a non-film type.

Here, the preferred embodiment of the crusher will be described. FIG. 3is a schematic side view of one example of a crusher used in the presentinvention; FIG. 4 is an enlarged view of part of FIG. 3; FIG. 5A is afront view of an opposite wall; FIG. 5B is a sectional view taken alonga line 5B—5B in FIG. 5A; FIG. 5C is a plan view of a connecting plate ofa chain conveyor; and FIG. 5D is a sectional view taken along a line5D—5D in FIG. 5C. FIG. 6A is a schematic side view of another example ofa crusher; and FIG. 6B is a schematic side view of a still furtherexample thereof.

The crusher illustrated has a chain conveyor (endless conveyor) 220 andan opposite wall (opposite member) 250. The chain conveyor 220transports articles carried on connecting plates 221 attached to a chain225 driven by sprockets 227, 227, by displacing the connecting plates221. This chain conveyor 220 is disposed to have a downward inclinationtoward the conveying direction indicated by arrow in the drawing totransport the polymer mold products introduced into the crusher from amaterial introduction port 232 provided at an upper position of thecrusher, while carrying the mold products on the connecting plates 221.As shown in FIG. 5C, a plurality of crushing edges 222 (in the drawing,two rows of eighteen edges) are provided on the respective connectingplate 221 of the chain conveyor 220 with sharp ends thereof projectingout of the conveyor. In this regard, instead of the crushing edges 222,crushing pins may be provided.

The opposite wall 250 extends in the vertical direction and has anopposite surface 255 opposed to an end portion of the chain conveyor 220as seen in the conveying direction (a left end portion in FIG. 3). Inthe vicinity of a point at which this opposite surface 255 is closest tothe chain conveyor 220 (in the vicinity of the lower end in thedrawing), a plurality of crushing edges 252 are provided while directingtoward the chain conveyor 220. In this regard, instead of the crushingedges 252, crushing pins may be provided. As shown in FIG. 5, thecrushing edges 252 on the opposite wall 250 and the crushing edges 222on the chain conveyor 220 are provided to have different phases fromeach other not to collide with each other even though both the crushingedges most closely approach. In the opposite wall 250, slits 256 areprovided so that tip ends of the crushing edges 222 on the chainconveyor 220 can enter the same not to collide with the opposite wall250 when the crushing edges 222 most closely approach the opposite wall250. FIG. 4 illustrates a manner in which the crushing edges 222 of thechain conveyor 220 most closely approach the opposite wall 250 and thetip ends of crushing edges 222 enter the slits 256.

In the crusher thus structured, the polymer mold products introducedfrom the material introduction port 232 into the crusher and conveyed bythe chain conveyor 220 are sheared by the crushing edges 222 and 252 androughly crushed while being compressed into a zone in which the chainconveyor 220 and the opposite wall 250 are close to each other.

FIG. 6A illustrates a variation of FIG. 3. The crusher shown in FIG. 6Ais provided with a guide 259 at a lower end of the opposite wall 250.This guide 259 operates, when the mold product conveyed by the chainconveyor 220 is of a flat-shape and oriented in the vertical direction,to prevent the mold product from escaping from the compression caused bythe chain conveyor 220 and the opposite wall 250 and the shearing actionof the crushing edges 222, 252 and falling down while not being crushed.

In this regard, while the crushing edges are provided both in the chainconveyor 220 and the opposite wall 250 in the embodiments shown in FIGS.3 and 6A, they may be provided in at least one of the both. However, ifthey are provided in both of them, the shearing action of the crushingedges is more enhanced.

In a crusher shown in FIG. 6B, two chain conveyors 220 and 250 a areprovided so that a distance between the both becomes gradually smallerin the conveying direction. According to this crusher, the upperinclined chain conveyor 250 a has a function as the opposite member. Thecrushing edges 222 and 252 a of the respective conveyors 220 and 250 areprovided to have different phases from each other not to collide witheach other even though both the crushing edges most closely approach

While two chain conveyors 220, 250 a have crushing edges 222, 252 a,respectively, in the embodiment shown in FIG. 6B, these may be providedon at least one of the conveyors. If the crushing edges are provided onboth the conveyors, the shearing operation of the crushing edges can bemore assuredly carried out. In the arrangement shown in FIG. 6B, theupper chain conveyor 250 a may be replaced with a slanted opposite wallhaving the same inclination as the conveyor 250 a. Alternatively,rollers may be provided. That is, it is sufficient that there is anarrangement for transporting the polymer mold products by the conveyormeans and pushing the same into a gap between the conveyor means and theopposite member so that the mold products are roughly crushed whilebeing compressed by the crushing edges or pins.

In this regard, a continuous system may be arranged from the arrangementshown in FIG. 3 or 6 by providing a fine crusher (for more finelycrushing the coarsely crushed pieces) subsequent thereto.

Now return to FIG. 2 wherein the conveyor device 49 transports the bagsin which the crushed resinous pieces are packed at a predetermined speedV and stops the same if necessary. If it is expected that a more time isrequired for the identification of resin, for example, because of a slowcalculating speed of the resin identification device 41 (describedlater), the stop of the conveyor device will be necessary. The conveyordevice 49 may include a conveyor with trays and if an expected arrivaltime has been reached, the corresponding tray is inclined to throw downthe bag carried thereon into a recovery box beneath the same. Theexpected arrival time is a time instant obtained by adding a time periodnecessary for a certain bag in which a resin of kind A are packed to beconveyed to a recovery box for the resin A to a time instant at whichthe resin in the bag has been identified as A. The corresponding tray isa tray on which the certain bag is placed. In this regard, while thecrusher 21 and the conveyor device 49 (and the resin identificationdevice 41 or others) are provided in the same factory in FIG. 2, theboth may be provided in different factories, respectively, such that theresinous pieces crushed by the crusher 21 and stuffed in the bag 25 aretransported to the factory in which the conveyor device 49 or others isprovided. In other words, even in such an arrangement, it is possible tosuppress the transportation cost to a lower level because the resin isreduced in volume.

The resin identification device 41 is a device for identifying a kind ofthe crushed resinous pieces in the bag 25 based on a Raman spectrumanalysis. That is, a laser beam is irradiated to the crushed resinouspieces in the bag 25 which passes a detection position (identificationposition) (or is made to stop for a while if a time period is requiredfor the identification), and reflected therefrom. A Raman spectrum isobtained from the reflected beam and sequentially compared with Ramanspectra of known resins to find the coincidence of Raman spectra of boththe resins to decide a kind of resin in the bag. For this purpose, theresin identification device 41 stores Raman spectra of various resinsobtained in advance.

The classified recovery device 47 a is for a resin A. Similarly, theclassified recovery device 47 b is for a resin B, and the classifiedrecovery device 47 c is for a resin C. If there are four kinds of resinsor more, the number of classified recovery devices may becorrespondingly increased. A distance between theclassification/recovery position of the classified recovery device 47 aand the detection position of the resin identification device 41 is a; adistance between the classification/recovery position of the classifiedrecovery device 47 b and the detection position of the resinidentification device 41 is b; and a distance between theclassification/recovery position of the classified recovery device 47 cand the detection position of the resin identification device 41 is c.When a current time reaches the expected arrival time, the classifiedrecovery device corresponding to the kind of resin in correspondence tothat expected arrival time is operated to recover the bag located at theclassification/recovery position of that classified recovery device intothe recovery box.

The classified recovery device is not limited to the illustrated one inwhich a tiltable tray of the conveyor is inclined to throw down the baginto the recovery box disposed beneath the conveyor. For example, amanipulator may be provided above the conveyor and lift the bag on theconveyor to recover the same. Alternatively, a pusher may be providedfor pushing the bag on the conveyor aside by a rod or the like. Or, theclassified recovery devices may not be individually provided incorrespondence to kinds of resins, but all the bags may be recovered bya single recovery device, from which the bags are distributed into therespective recovery boxes in correspondence to the kinds of resins.

FIG. 7 is a block diagram illustrating the relationship between inputsand outputs of a controller for the system, and FIG. 8 is a flow chartillustrating a procedure for controlling the identification andclassification/recovery of resins. The description will be made belowwith reference to FIGS. 7 and 8.

First, the conveyor device 49 starts (S01).

When the identification result (a kind of resin in the bag 25 passingthrough the identification position or stopping in a period necessaryfor the identification at the identification position) is input from theresin identification device 41 (i.e., the answer is YES at S11), theexpected arrival time at which the bag (packing the identified resin)reaches the classified recovery device (for example, the device 47 a) iscalculated based on a current time obtained from a clock IC 43, adistance to the classified recovery device determined in accordance witha kind of the identified resin (if the identified resin is a kind A,this distance is a to the classified recovery device 47 a) and aconveying speed V of the conveyor device 49, and stored in a memory (notshown) within a controller 45 in correspondence to the resin kind A(i.e., to the classified recovery device 47 s) (S13). In this regard,since the conveying speed V and the distance (a/b/c) are known, a timeperiod necessary for the transportation determined in accordance withkinds of resins may be added to the current time, instead of carryingout the above calculation.

If the current time reaches either one of the expected arrival timesstored in the memory (not shown) of the controller 45 (i.e., if theanswer is YES at S21), an operation command is issued from thecontroller 45 to the classified recovery device stored in correspondenceto this expected arrival time. Thereby, the above-mentioned classifiedrecovery device is operated to recover the bag located at theclassification/recovery position of the classified recovery device(S23). Thereafter, the expected arrival time and data of the classifiedrecovery device stored in correspondence thereto are deleted from thememory (S25).

Other preferred embodiments of the resin identification device will bedescribed in more detail below with reference to FIGS. 9 to 11.

(1) First Embodiment

FIGS. 9A, 9B and 10 schematically illustrate a first embodiment of apolymer conveying mechanism provided with an identification device,wherein FIG. 9A is a side view, FIG. 9B is a top view and FIG. 10 is asectional view taken along a line 10—10 in FIG. 9A. In the drawings,reference numeral 410 denotes a polyethylene bag (having a size of 23 cmlong, 17 cm wide and 40 μm thick) in which resin pieces crushed to havea suitable size (for example, so that 70% or more of the pieces have anequivalent diameter in a range from 1 to 50 mm) are packed, wherein theequivalent diameter is a diameter of a circle having the same area as aprojected area of an object.

The bag 410 is conveyed on a conveyor belt 440 driven by drive rollers441, 441 in the arrowed direction, and irradiated with a laser beam froma sensor element 421 in the midway of its travel, whereby a Ramanscattering can be detected. The detected signal is fed to anidentification and calculation device 420 in which a kind of resin isidentified. That is, the detected Raman spectrum is sequentiallycompared with those of various known resins stored in advance until theknown resin coinciding with the resin to be identified is found. Basedon the identification result, a timing for a dispensing operation iscalculated and a dispensing device 430 is operated at the calculatedtiming. Thereby, the bag 410 is removed from the conveyor belt 440 andput into a vessel in correspondence to a kind of the identified resin(either one of vessels 435 a, 435 b and 435 c). The dispensing timing isa timing at which the bag 410 of which the Raman scattering has beendetected at a position of the sensor element 421 to identify the kind ofresin reaches the vessel (either one of vessels 435 a, 435 b and 435 c)corresponding to the kind of resin packed in the bag.

According to the first embodiment, as illustrated, a plurality of slits400S of a predetermined length used as a light window for allowing alight beam to pass through the same (having a size of 10 mm wide and 20cm long) are arranged along a center portion of the width of theconveyor belt 440 at a predetermined pitch in the belt-runningdirection. The above-mentioned sensor element 421 is disposed at aposition in correspondence to the slit position beneath the conveyorbelt 440 in the vicinity of the inner surface of the conveyor belt 440.Thus, it is possible to maintain a distance between the light-receivingpart of the sensor element 421 and the bottom surface of the bag 410always at a predetermined short distance (for example, approximately 10mm) capable of detecting the Raman scattering, irrespective of shapes ofthe bags 410. Thereby, the high-precision resin identification can becarried out.

In this regard, a member for pressing the bag 410 onto the upper surfaceof the conveyor belt 440 may be provided at a position above the sensorelement 421 to prevent the bottom surface of the bag 410 from floatingupward from the upper surface of the conveyor belt 440, so that theabove-mentioned distance between the light-receiving part of the sensorelement 421 and the bottom surface of the bag 410 is maintainedconstant.

(2) Second Embodiment

FIG. 11 schematically illustrates a second embodiment of a polymerconveying mechanism wherein FIG. 11A is a side view and FIG. 11B is atop view. In the drawings, the same reference numerals are used fordenoting the same or similar parts as those in FIG. 9, and theexplanation thereof will be eliminated.

According to the second embodiment, as illustrated, a window plate 422having a light window for allowing a light beam to pass through the sameis disposed at a position on the lateral side of a conveyor belt 440 a,and is also used as a stopper member. A sensor element 421 is providedat a position on a side of the window plate 422 opposite to the conveyorbelt 440 a so that the light receiving part of the sensor element 421confronts the window plate 422. At a position opposite to the windowplate 422, a plate-like curved guide 423 is provided directly above theconveyor belt 440 a, while interposing the conveyor belt between thewindow plate and the curved guide. This guide 423 operates to push thebag 410 transported on the conveyor belt 440 a toward the window plate422 and cause the bag 410 to be in contact with the window plate 422.According to this structure, it is possible to maintain a distancebetween the light-receiving part of the sensor element 421 and thelateral surface of the bag 410 at a thickness of the window plate 422(for example, approximately 10 mm), irrespective of shapes of the bags410. In other words, it is possible to maintain the distance at a valueas small as capable of detecting the Raman scattering. Thereby, thehigh-precision resin identification can be carried out.

Instead of the guide 423 formed of a curved plate as in the illustratedembodiment, one or two rollers or more may be used for the same purpose.In such a case, the roller may be either a freely rotatable type or onedriven to rotate in synchronism with the conveyor belt 440 a.

While an endless belt is used as a conveyor means in the above-mentionedembodiment, the conveyor means according to the present invention shouldnot be limited to the endless belt, provided it is capable oftransporting the polymer to be detected while maintaining apredetermined short distance between the light-receiving part of thesensor element 421 and the polymer. For example, the conveyor means maybe of a type for transporting the bag 410 carried on a tray.

[2] Rinsing System 600

Next, the cleaning system 600 will be described.

FIGS. 12 to 14 illustrate a structure of the continuous cleaning device600, wherein FIG. 12 is a schematic cross-sectional view, FIG. 13 is aschematic side sectional view and FIG. 14 is a detailed illustration ofa drainage line 669 for adjusting a water level.

The continuous cleaning device 600 has a vessel 660 and rotary bodies662. In FIGS. 12 and 13, the vessel 660 may be formed of a metal such asstainless steel. An entrance port 663 for crushed resinous pieces isprovided at one end of an upper wall of the vessel 660, and an exit port668 for the crushed resinous pieces is provided in a lateral wall on theopposite end side. A water feeding port 664 is provided at at least oneposition of the upper wall of the vessel 660, and a drainage port 666 isprovided at at least one position of the lower wall of the vessel 660. Adrainage line 669 for adjusting a water level is connected to thedrainage port 666.

A predetermined amount of crushed resinous pieces is continuouslyintroduced into the vessel 660 through the entrance port 663, conveyedalong the same and discharged from the exit port 668. In this process,preferably, the introduction speed and the discharge speed of thecrushed resinous pieces are approximately equal to each other andmaintained roughly constant. A feeding speed of water to be suppliedfrom the water feeding port 664 is preferably controlled so that a waterlevel determined by the water level adjusting pipe 669 b is maintained,while taking a draining speed of water from an open end of the waterlevel adjustment drainage line 669 into account. By adjusting theintroduction and discharge speeds of the crushed resinous pieces andthose of water, constant amounts of crushed resinous pieces and waterare always conveyed through the vessel 660. Accordingly, the crushedresinous pieces are evenly cleaned and, as a result, the surfaces of thecrushed resinous pieces are free from the foreign matters left thereon,and prevented from being excessively scraped off.

In the drainage port 666 provided in the bottom wall or others of thevessel 660, slits or punched plate are disposed. Also, in the drainageport 666, the water level adjustment drainage line 669 is connected. Thewater level adjustment drainage line 669 has a drainage pipe 669 aconnected to the drainage port 666 and standing upward on the lateralside of the vessel 660 and a water level adjustment pipe 669 b fitted tothe interior of the drainage pipe 669 a in a slidable manner. Betweenthe inner surface of the drainage pipe 669 a and the outer surface ofthe water level adjustment pipe 669 b, an O-ring 669 c is interposed tokeep the water-tight sealing. By moving the water level adjustment pipe669 b upward and downward, it is possible to adjust the water level inthe cleaning device 600 and maintain a predetermined water level.

While the water feeding port 664 and the drainage port 666 are providedat one position, respectively, in the illustrated embodiment, they maybe provided at a plurality of positions, respectively. When the waterfeeding ports 664 are provided at a plurality of positions from one endto the other end of the vessel 660, it is possible to quickly guide dustor others generated by the cleaning operation to the drainage ports 666and drain the same outside through the water level adjustment line 669.Further, it is also possible to prevent the dust or others from stickingagain to the crushed resinous pieces.

Openings provided in the drainage port 666 such as slits or holes of apunched plate have a size to allow water or dust to pass through thesame but prevent the crushed resinous pieces from passing. The slit ispreferably of a size in a range from approximately 0.3 to 2 mm in viewof the mechanical strength. While the drainage port 666 may be providedin either of the bottom wall or the lateral wall, the bottom wall ispreferable in view of the adjustment of the water level. In this regard,if the drainage port is provided in the lateral wall, the positionthereof is preferably as low as possible, of course.

An open end of the water level adjustment pipe 669 b opens to theatmosphere so that the water level in the vessel 660 is generally equalto a height of the open end of the water level adjustment pipe 669 b.Thereby, even if the feed rate of water varies, the water level ismaintained constant and excessive water is drained from the open end ofthe water level adjustment pipe 669 b. The drained water may beaccumulated in a tank and reused after being pumped up and filtratedthrough a filter to remove dust or others therefrom.

The rotary shaft 662 is provided with screw blades 662 c for cleaningthe crushed resinous pieces while conveying the same from the entranceport 663 to the exit port 668, and cleaning plates 662 a and cleaningpins 662 b for scrubbing or scraping off foreign matters from thesurface of the crushed resinous pieces while imparting shock thereto,all of which are alternately arranged. Either one of the cleaning plate662 a or the cleaning pin 662 b may be eliminated, although the combineduse thereof is preferable.

A diameter of the screw blade 662 c, a thickness of the cleaning plate662 a and a length of the cleaning pin 662 b are not limited, providedthe efficient cleaning is achievable. The screw blades 662 c may have agenerally equal diameter; the cleaning plates 662 a may have generallyequal diameter and thickness; and the cleaning pins 662 b may have agenerally equal length. Also, the number of screw blades 662 c forcleaning the crushed resinous pieces while conveying the same ispreferably two or three per one zone. An axial length of the screw blade662 c per one zone is preferably 0.5 to 3 relative to a diameter. Whilethese screw blades 662 c, the cleaning plates 662 a and the cleaningpins 662 b are alternately arranged, the number thereof disposed in onezone may be equal in all zones or different from those of other zones.

A pitch of the screw blades 662 c must be determined by taking arotational speed of the rotary shaft into account. Since the rotaryshaft is necessarily made to rotate at a relatively high speed foreffectively abrading and cleaning the crushed resinous pieces, the pitchis preferably in a range from 0.3 D to 1.5 D wherein D represents adiameter of the screw blade 662 c. If the pitch is less than 0.3 D, agap between adjacent two screw blades is so small that the crushedresinous pieces may be caught in the gap and rotate together with thescrew blades to disturb the transportation or the cleaning. Also, thecrushed resinous pieces caught in the gap may melt to disable thecontinuation of cleaning operation. On the other hand, if the pitchexceeds 1.5 D, the conveying efficiency is lowered. In this regard, whenthe conveying efficiency of the screw blade 662 c is excessively largeand thus a dwell time of the crushed resinous pieces becomesinsufficient in the area wherein the cleaning plates 662 a or thecleaning pins 662 b are provided, part of the screw blade may be cut offso that a balance is adjustable between the conveying capacity and thecleaning operation.

Shapes of the cleaning plate 662 a are not limited. For example, thecleaning plate may be circular or polygonal, such as triangular orquadrangular, as seen in the axial direction of the rotary shaft 662.The cleaning plate 662 a is not necessarily symmetric in shape withrespect to the rotary shaft 662. Also, it may be slanted to the rotaryshaft 662 to have a conveying function. The cleaning plates inclined inthe conveying direction and in the opposite direction thereto may becombined with each other to enhance the cleaning efficiency. The same istrue to the cross-sectional shape of the cleaning pin 662 b, which maybe circular or polygonal such as triangular or quadrangular. Thepolygonal cross-section is favorable because the cleaning efficiencybecomes higher. The cleaning pin 662 b is not necessarily projectedvertical to the circumference of the rotary shaft 662 but may beinclined at a proper angle.

The rotational speed of the rotary shaft 662 has a proper range variablein accordance with sizes of devices, kinds of crushed resinous pieces ordegrees of cleaning demanded. Generally, a linear speed of a tip end ofthe cleaning plate 662 a or the cleaning pin 662 b is preferably in arange from 0.5 to 20 m/sec, more preferably from 1 to 10 m/sec. In therotational speed under which the linear speed is less than 0.5 m/sec, itis impossible to sufficiently clean the surface of the crushed resinouspiece even if the treatment time is prolonged. Contrarily, if the linearspeed exceeds 20 m/sec, the interior temperature of the cleaning devicerises to soften and be liable to melt the crushed resinous pieces, whichis unfavorable because a large driving power is necessary.

At least part of surfaces to be in contact with the crushed resinouspieces; that is, the inner surface of the vessel 660 and surfaces of thescrew blade 662 c, the cleaning plate 662 a and the cleaning pin 662 b;is roughened to constitute an abrasive surface. Accordingly, the foreignmatters on the surface of the crushed resinous piece can be efficientlyscrubbed or scraped off. A depth of the irregularity on the roughenedsurface is preferably in a range from 40 to 2000 μm, more preferablyfrom 50 to 1000 μm, most preferably from 60 to 500 μm. If the depth isless than 40 μm, the foreign matters could not be sufficiently removed.On the other hand, if exceeding 2000 μm, the surface of the crushedresinous piece is excessively scraped off to unfavorably lower therecovery percentage of resin. A degree of the above-mentionedsurface-roughening is not necessarily constant from the entrance port663 to the exit port 668. The cleaning efficiency may be adjustable, forexample, by changing the roughening degree to be coarser toward theentrance port 663 and relatively smoother toward the exit port 668.Also, the cleaning efficiency may be enhanced, for example, by mixingvarious abradants with water.

While a two-shaft type cleaning device is illustrated in the drawing,this is merely one example and a single-shaft type or a multi-shaft typeincluding a three- or more shaft type may be adopted. When thesingle-shaft type is adopted, however, the movement of the crushedresinous pieces becomes monotonous in the device to lower the cleaningefficiency. Contrarily, the device having three shafts or more iscomplicated in structure and expensive.

An interior space of the cleaning device may be suitably designed inaccordance with throughputs or others thereof. An interior dimension ofthe vessel 660 in the direction vertical to the rotary shaft 662 may besuitably selected in accordance with a diameter of the screw shaft 662 cand a necessary gap between the inner surface of the vessel 660 and atip end of the screw blade 662 c. An axial dimension of the rotary shaft662 is 5 to 30 times, preferably 10 to 30 times a diameter of the screwblade 662 c.

If the axial dimension is less than five times the diameter of the screwblade 662 c, the crushed resinous pieces are conveyed to the exit port668 with part of them being not sufficiently cleaned, which degrades thequality of recycled resin material due to the mixture of theinsufficiently cleaned crushed resinous pieces. If the axial dimensionexceeds 30 times the diameter of the screw blade 662 c, the mechanicalstrength of the rotary shaft 662 must be increased or a support systemthereof must be changed, which makes it difficult to prevent the innersurface of the vessel 660 from coming in contact with the screw blade662 c or others and increases a cost of the device to a great extent.

While the above description has been made on a continuous type cleaningdevice, a batch type may be adopted. FIG. 15 illustrates a batch typecleaning device of a vertical type as one example thereof.

A vessel 661 is preferably cylindrical and formed of a metal such asstainless steel. An entrance port 663 for introducing crushed resinouspieces is provided on the upper surface of the vessel 661, and an exitport 668 for discharging the crushed resinous pieces is provided on thebottom surface thereof. A piston-shaped valve 621 is provided in theexit port 668, so that the valve is flush with the bottom surface of thevessel body when the valve is closed. After the cleaning has completed,the piston-shaped valve 621 is opened to take the crushed resinouspieces out of the vessel.

On the lateral surface of the vessel 661, a water supply port 664 isprovided at an upper position and a drainage port 666 is provided at alower position. A water level adjustment drainage line 669 shown in FIG.14 is connected to the drainage port 666. Alternatively, the watersupply port 664 may be provided on the upper surface of the vessel 661,and the drainage port 666 may be provided on the lower surface of thevessel 661. While the drainage port 666 is formed throughout a lowerarea of the lateral surface of the vessel 661 in FIG. 15, it may beprovided on part of the lower area of the lateral surface. Further,there is no limitation in positional relationship between the entranceport 663 and the exit port 668, but they are preferably provided on adiagonal of the cross-section of the vessel 661. If so, all the crushedresinous pieces are evenly and efficiently cleaned.

There is no limitation in shape of an agitator blade 603, but a paddletype blade or a lattice type blade having a large surface area ispreferably used. The agitator blades 603 are arranged at a center of thevessel 661, and at least part of the inner surface of the vessel 661 andthe surface of the agitator blade is roughened. A degree of thisroughening, a ratio between the crushed resinous pieces and water and asize of openings such as slits or holes of a punched plate provided inthe drainage port 666 are similar to those in the above-mentionedhorizontal type continuous cleaning device.

[3] Recovery System 800

Then, the description will be made on the recovery system 800.

The recovery system 800 operates to separate foreign matters from amixture of the foreign matters and crushed resinous pieces cleaned bythe cleaning system 600 and recover the crushed resinous pieces. Therecovery system 800 may include various systems; for example, a systemfor removing metallic material by using magnetic force, a system forremoving foreign matters by rinsing and a system for removing foreignmatters with wind.

A device illustrated in FIG. 16 separates the crushed resinous piecesfrom the foreign matters by rinsing the mixture thereof with water,discharges the foreign matters thus separated together with water andrecovers the remaining crushed resinous pieces.

On the surface of the crushed resinous piece cleaned by the cleaningsystem 600 as described above, foreign matters (dust derived from coatedfilm, plated layer or label) scrubbed or scraped off from the crushedresinous pieces by the cleaning operation are adhered. This mixture (ofthe crushed resinous particles and the foreign matters) is initiallyintroduced into a continuous type rinsing device 881 and rinsed withwater. Most of the foreign matters adhered to the surface of the crushedresinous pieces are removed therefrom together with water in thisprocess. This water may be reused after being filtrated.

The crushed resinous pieces thus rinsed are transferred via a pipe 882to a centrifugal dryer 883 in which the dehydration is carried out. Thecrushed resinous pieces thus dehydrated are conveyed while vibrating ona vibratory screen 884, whereby the residual foreign matters areremoved. Thereafter, the pieces are collected by a predeterminedrecovery means. In this regard, subsequent to the vibratory screen 884,means 889 may be provided for further removing metallic particles byusing magnetic force or foreign matters by using wind.

Thus, the recycling of resin is carried out.

EXAMPLES

Results of the crushing operation carried out by using theabove-mentioned embodiment of the crusher described above are shown inTable 1 of FIG. 17. The specifications of this crusher are as follows:

Size of entrance port: 300 mm×600 mm

Width of chain conveyor: 340 mm

Motor: 5.5 kW

Rotational speed of conveyor: 50 rpm

Number of crushing blades in connecting plate: 2 rows×18/a plate

Opposite member: fixing plate with slits

I-[1] Example A

Twenty resinous parts were manually extracted from discarded copyingmachines. Although having various sizes and shapes, the parts were allmold products having a plate-thickness of approximately 2 to 3 mm. Themaximum length thereof was 630 mm. These were classified into two groupsin accordance with the criterion whether or not the product has a sizein which two of a length, a width and a height are 280 mm×170 mm orless.

[1-1] Five parts had a size of 280 mm×170 mm or less, a total weight ofwhich was 2.3 kg.

[1-2] Fifteen parts had a size exceeding 280 mm×170 mm, a total weightof which was 9 kg.

These mold products were crushed by the crusher shown in FIG. 3 (thespecifications of which were as described above).

Results were shown in Table 1 of FIG. 17. In Table 1, an equivalentdiameter of a projection circle in Table 1 is defined as a diameter of acircle having the same area as a projected area of a particle (seeKAGAKU KOGAKU BINRAN, 5th edition, p.219). In this Example, an image ofabout 100 particles placed on a flat surface while taking care not tooverlap with each other was shot, from which the number and theindividual area are measured by an image-processing technique. Then atotal of the areas was divided by the number of particles to obtain anaverage area, from which a diameter of a circle having the same area iscalculated.

I-[2] Comparative Example A

A trial was made to treat the same resin mold products as used inExample A with a small size crusher UG-280 (effective aperture 280mm×170 mm, 5.5 kW) manufactured by K.K. HORAI and added with a screen of15 mm

However, the resin mold products in the group [1-2] (exceeding 280mm×170 mm) could not be introduced into the small size crusher UG-280 ofK.K. HORAI and thus could not be crushed.

II-[1] Example B (Regarding the Identification)

The following three mold products 1. to 3. of different kinds of resins(a box having a size of 15 cm×10 cm×10 cm and a thickness of 3 mm) wereindividually crushed by the crusher UG-280 manufactured by K.K. HORAI(with a screen of 20 mm mesh). An average size of the crushed resinouspiece was approximately 10 mm as represented by an equivalent diameter,wherein the equivalent diameter is a diameter of a circle having thesame area as a projected area of the crushed resinous piece.

The above crushed resinous pieces are respectively packed in separatebags (made of polyethylene and having a size of 23 cm long, 17 cm wideand 40 μm thick). Kinds of the resins were identified by a resinidentification device (RP-1, manufactured by Spectracode; based on theRaman spectrum analysis), upon which a time required for theidentification was measured. Results are shown in Table 2 of FIG. 18. InTable 2, ∘ represents cases wherein all the samples could be identified,and X represents cases wherein there are samples not identified.

1. Acrylonitrile-butadiene-styrene

2. Polystyrene

3. Polycarbonate/acrylonitrile-butadiene-styrene

II-[2] Comparative Example B (Regarding the Identification)

Comparative example B was carried out in the same manner as in ExampleB, except that the above-mentioned three resin mold products 1. to 3.were crushed all together, not separately, in the crusher and the threekinds of resinous pieces were identified as they are by the resinidentification device, respectively, without being packed in the bag.Results are shown in Table 2 of FIG. 18.

In Table 2, the number of test samples was assumed by the followingequation:

Number of test samples=weight of resin mold product beforecrushing/standard weight of crushed piece

The weight of the resin mold product before crushing was 702 g and thestandard weight of the crushed piece was 0.259 g, whereby the number ofthe test samples was 2700. This value is about 900 times that in ExampleB. In this regard, an average weight of ten disk-like pieces having theequivalent diameter of approximately 10 mm was used as the standardweight of the crushed piece.

In Table 2, the time required for the identification was assumed by thefollowing equation:

Time required for identification=all weights of crushed pieces/weight ofcrushed pieces which could be identified within one minute

All the weights of the crushed pieces was 702 g and the weight of thecrushed pieces which could be identified within one minute was 5.21 g,whereby the time required for the identification was 135 minutes. Thisvalue is about 900 times that in Example B. In this regard, in thecrushed pieces having the equivalent diameter of 1 mm or less, therewere those difficult to be positioned to the identification device orimpossible to be identified because the intensity of Raman spectrumbecomes weak.

Next, an example regarding the cleaning system will be described.

OA apparatuses collected from the market were disassembled to separatehousings made of ABS resin which were then crushed by using a marketedcrusher (UG-280; manufactured by K.K. HORAI, with a screen of 10 mmmesh) into crushed resinous pieces and subjected to a cleaningtreatment. There were paper seals on part of the housing and manycontaminants on the surface due to a long time use or the collection,disassembly or classification operation. Hereinafter, such crushedresinous pieces are referred to as crushed pieces (A).

In a similar manner, housings made of ABS resin and having a coating onthe surface thereof were crushed into crushed pieces (B) which were thencleaned.

III-[1] Example C (Regarding the Cleaning by the Horizontal TypeContinuous Cleaning Device Shown in FIGS. 12 and 13)

(1) Cleaning device used

A diameter of a screw blade provided on a rotary shaft of the cleaningdevice was 100 mm and a length of the device was 25 times the diameterof the screw blade; i.e., 2.5 m. A drainage port had slits of 1.2 mmwide. A water level was maintained somewhat higher than the rotary shaftby the water level adjustment pipe, so that a weight of crushed pieces(A) and that of rinsing water are generally equal to each other.

Further, the screw blades and cleaning plates constituted bysemicircular disks arranged on the rotary shaft at a pitch of 40 mm witha phase thereof being shifted at 90 degrees to each other werealternately disposed on the rotary shaft so that a ratio of an axiallength to the diameter thereof becomes 2 to 4. Part of the screw bladewas cut off to adjust the conveying capacity. The inner surface of thevessel and the surfaces of the screw blades and the cleaning plates wereroughened to have the irregularity of 50 to 100 μm deep.

(2) Cleaning operation

Crushed pieces (A) were introduced into the entrance port of thiscleaning device at a rate of 50 kg/hr. On the other hand, water was fedfrom the entrance port at a rate of 30 kg/hr and also from two waterports provided in the lengthwise intermediate portion of the device.These water supply rates were regulated so that a drainage rate from anopen end of the drainage line becomes 100 kg/hr.

The cleaning operation was carried out at a rotational speed of therotary shaft of 400 rpm (corresponding to a linear speed of 2.1 m/sec ata tip end of the cleaning plate) to obtain a slurry in which dust suchas the paper seals blocked to pass by the slits is mixed with thetreated crushed pieces (A) from the exit port. The slurry was dispersedon the vibratory screen of 2 mm mesh while spraying water from above toseparate and remove pieces of the paper seals or dust therefrom.Thereafter, the crushed pieces were dehydrated through a centrifugaldryer and dried. Then, through a wind classifier, foreign matters havinga small specific weight which could not removed by the water spray wereseparated and removed to obtain completely cleaned crushed pieces.

(3) Inspection of foreign matters

Crushed pieces of 10 g were compression-mold between a pair of cleanaluminum foils put in a gap between stainless steel plates at atemperature of 220° C. and a pressure of 4 MPa to result in a sheet ofapproximately 200 mm diameter. Thereafter, the aluminum foils werepeeled off from this sheet, and opposite sides of the sheet wereobserved by a magnifying glass to count the number of foreign matters.Results are shown in Table 3 of FIG. 19.

III-[2] Comparative Example C

A trial was made to clean the crushed pieces (A) in the same manner asin Example C, except that water is not used. In a short time afterbeginning the introduction of crushed pieces, however, the crushedpieces began to melt, whereby a load became large to disable theoperation.

III-[3] Comparative Example D

A rotational speed at which the crushed pieces are not melted wasstudied in Comparative example C, and it was found that such a speed is50 rpm (corresponding to a linear speed of 0.26 m/sec at a tip end ofthe cleaning plate). The cleaning operation was carried out at thisrotational speed in the same manner as in Comparative example C in whichwater is not used. After being cleaned, the crushed pieces (A)discharged from the exit port were post-treated in the same manner as inExample C to separate and remove the foreign matters. Foreign mattersleft in the crushed pieces were observed in the same manner as inExample C. Results are shown in Table 3 of FIG. 19.

III-[4] Example D

The crushed pieces (B) were cleaned in the same manner as in Example Cexcept that a water supply rate from the intermediate portion increasesso that a drainage rate is regulated to 200 kg/hr at the open end of thedrainage line. After being cleaned, the crushed pieces (B) dischargedfrom the exit port were post-treated in the same manner as in Example Cto separate and remove foreign matters. Foreign matters left in thecrushed pieces were observed in the same manner as in Example C. Resultsare shown in Table 3 of FIG. 19.

III-[5] Comparative Example E

The cleaning was carried out in the same manner as in Example D exceptthat the rotational speed of the rotary shaft decreases to 50 rpm. Afterbeing cleaned, the crushed pieces (B) discharged from the exit port werepost-treated in the same manner as in Example C to separate and removeforeign matters. Foreign matters left in the crushed pieces wereobserved in the same manner as in Example C. Results are shown in Table3 of FIG. 19.

III-[6] Example E (Regarding the Cleaning by the Batch Type CleaningDevice of a Vertical Type Shown in FIG. 15)

This cleaning device had a vessel having an inner diameter of 400 mm anda height of 500 mm, in which lattice type blades having an outerdiameter of 360 mm is provided at a center. The inner surface of thevessel and all surfaces of the lattice type blades were roughened tohave the irregularity of 200 to 300 μm deep.

The crushed pieces (A) of 22 kg and water of 20 kg were introduced intothis cleaning device, and a height of the water level adjustment pipe isregulated to the water level at this instant. The cleaning operation wascarried out for 20 minutes by rotating the lattice type blade at 300 rpmand supplying and draining water at a rate of 20 l/hr. After beingcleaned, the cleaned crushed pieces (A) were taken out therefrom byopening the piston-shaped discharge valve. The crushed pieces werepost-treated in the same manner as in Example C to separate and removeforeign matters. Foreign matters left in the crushed pieces wereobserved in the same manner as in Example C. Results are shown in Table3 of FIG. 19.

III-[7] Comparative Example F

The cleaning operation was carried out in the same manner as in ExampleE except that a crusher in which the inner surface of the vessel andsurfaces of the agitator blades are not roughened. After being cleaned,the cleaned crushed pieces (A) were taken out therefrom by opening thepiston-shaped discharge valve. The crushed pieces were post-treated inthe same manner as in Example C to separate and remove foreign matters.Foreign matters left in the crushed pieces were observed in the samemanner as in Example C. Results are shown in Table 3 of FIG. 19.

It is apparent from Table 3 of FIG. 19 that there are extremely lessforeign matters in the crushed pieces after being cleaned by rougheningpart of the crusher to be in contact with the crushed pieces.Particularly there are none of foreign matters, of which the maximumlength exceeds 0.25 mm. On the other hand, it is also apparent that; inComparative example C, the operation of the crusher is impossible due tothe melting of crushed pieces; in Comparative examples D and F,particularly in D, a number of foreign matters are left in the treatedcrushed pieces; and in Comparative example E, the number of foreignmatters is uncountable because of a large amount of remnants derivedfrom coated film. In other words, Comparative examples are all extremelyinferior.

The present invention has been described in detail with respect topreferred embodiments, and it will now be apparent from the foregoing tothose skilled in the art that changes and modifications may be madewithout departing from the invention in its broader aspects, and it isthe intention, therefore, in the appended claims to cover all suchchanges and modifications as fall within the true spirit of theinvention.

What is claimed is:
 1. A resin recycling system comprising crushingmeans for individually crushing resin mold products into crushedresinous pieces in which 70% or more of the crushed resinous pieces havean equivalent diameter in a range from 1 to 50 mm; packing means forseparately packing the individually crushed resinous pieces the saidpacking means including a bag having a transparent portion;classification means for irradiating a light beam to the individuallycrushed resinous pieces through the transparent portion of the bag andidentifying a kind of the crushed resinous pieces based on a reflectedbeam therefrom, and clarifying the bags into respective kinds of resins;and cleaning means capable of taking the crushed resinous pieces outfrom the bag and cleaning the crushed resinous pieces to remove foreignmatters adhered on the surface thereof said cleaning means comprising acleaning vessel, an agitating member provided in the cleaning vessel,and an abrasive surface provided on at least part of the inner wall ofthe cleaning vessel and/or the surface of the agitating member.
 2. Aresin recycling system as defined as claim 1, further comprisingrecovery means for separating foreign matters from a mixture of thecrushed resinous pieces and the foreign matters, and recovering thecrushed resinous pieces.
 3. A resin recycling system as defined by claim1, further comprising: conveyer means for conveying the bag and whereinsaid classification means comprises identification means, provided inthe vicinity of a predetermined identification position on a conveyingpath of said conveyer means, for irradiating a light beam to theindividually crushed and separately packed resinous pieces through thetransparent portion of the bag passing by the identification positionand identifying the kind of crushed resinous pieces based on a reflectedbeam therefrom, and storage means for storing the identified kind ofcrushed resinous pieces and being capable of estimating an expectedarrival time at which the bag of the crushed resinous pieces would reacha predetermined classification position on the conveying path.
 4. Aresin recycling system comprising: a crusher that includes an endlessconveyor for conveying individual polymer mold products, and an opposedmember having an opposed surface confronting at least one end of saidendless conveyer on a conveying-directional side and disposed so that adistance between the opposed surface and a conveying surface of saidendless conveyer becomes smaller in a conveying direction, whereincrushing edges or crushing pins are provided on at least one of theconveying surface of said endless conveyer and the opposed surface ofsaid opposed member, and a gap between the conveyor and the opposedmember is formed to crush the resinous pieces with said crushing edgesor pins; a packaging device including a bag having a transparentportion; an identification device for irradiating a light beam to thecrushed resinous pieces through the transparent portion of the bag anddetecting the reflected beam or the dispersed beam from the crushedresinous pieces by a sensor element, and identifying a kind of thepolymer product based on a detected result, wherein said sensor elementis disposed at a predetermined position in the vicinity of a conveyingpath of the crushed resinous pieces; and a device for cleaning thecrushed pieces that include a vessel and agitating blades, wherein thevessel has an entrance port for crushed resinous pieces and a watersupply port, both provided in an upper portion thereof, and an exit portfor the crushed resinous pieces and a drainage port, both provided in alower portion provided thereof; and drainage line for adjusting a waterlevel being connected to the drainage port, and at least part of thesurface of the vessel and/or surfaces of the agitating blades beingroughened to make them abrasive.